Neurosurgical interventions are emerging as treatments for a variety of intractable neurological conditions, including movement disorders, pain and epilepsy. Current techniques for optimization of stereotactically targeted neurosurgical interventions, such as RF ablation and deep brain stimulation, involve high resolution imaging and electrophysiological mapping. At present, electrophysiological mapping involves penetrating the computed target structures with single-channel movable microelectrodes to identify the neuronal structure boundaries. Each microelectrode is advanced very slowly, stopping to examine individual cells and to record the firing frequency and pattern. This mapping procedure is tedious and time-consuming. The proposed Deep Brain Microelectrode Array (DBMA) will consist of 24 electrode sites positioned in a bi- linear arrangement allowing multiple brain regions spanning 12 mm or more to be monitored simultaneously, greatly increasing the efficiency of the mapping procedure. The proposed Phase I project will concentrate on developing a prototype device that is dimensionally suitable for mapping deep brain structures in the human. Feasibility of fabrication and device functionality will be validated through a series of bench and animal tests. Possible enhancements to the DBMA device (through a Phase II project) might include recording sites optimized for unit and field recording and sites for stimulation. In order to meet the goals of the project, NeuroNexus Technologies, a leading supplier of microfabricated, microscale neural probes, will team with FHC, Inc., a leading supplier of intraoperative microelectrodes for recording and stimulation during functional neurosurgical procedures. [unreadable] [unreadable]